nevrotransmitter

A neurotransmitter is a chemical messenger that transmits signals across a synapse from a presynaptic neuron to a postsynaptic cell. In English the standard spelling is neurotransmitter, while in some languages the term is rendered as nevrotransmitter. They enable rapid, point-to-point communication within neural circuits and are essential for sensory perception, motor control, and cognitive processes.

Classifications include small-molecule transmitters, neuropeptides, purines, and gases. Small-molecule transmitters include acetylcholine, dopamine, norepinephrine, serotonin, glutamate, and gamma-aminobutyric acid (GABA). Neuropeptides such as substance P and endorphins act over longer timescales. Other classes include purines like ATP and the gas nitric oxide (NO). These chemicals can function as core neurotransmitters or as co-transmitters that modulate signaling.

Release and termination: neurotransmitters are stored in vesicles at the presynaptic terminal and released in response to calcium influx. They bind to specific receptors on the postsynaptic membrane, producing excitatory or inhibitory effects via ion channels (ionotropic receptors) or signaling cascades (metabotropic receptors). Termination occurs through reuptake into the presynaptic cell, enzymatic degradation, or diffusion away from the synapse.

Functions and clinical relevance: neurotransmitter systems regulate mood, attention, learning, movement, and autonomic functions. Imbalances or dysfunctions are associated with conditions such as depression, Parkinson’s disease, schizophrenia, and epilepsy. Many medications target neurotransmitter systems by altering synthesis, release, receptor activity, or reuptake, underscoring their central role in health and disease.